Mortuary + Grinding Station + Phyrexian Walker + Bolas's Citadel

Mortuary

Grinding Station

Phyrexian Walker

Bolas's Citadel

How it works

1. Activate Grinding Station by tapping it and sacrificing Phyrexian Walker
2. When Phyrexian Walker dies, Mortuary triggers, putting Phyrexian Walker from your graveyard onto the top of your library.
3. Resolve the Grinding Station ability.
4. Cast Phyrexian Walker from the top of your library by paying 0 life.
5. When Phyrexian Walker enters, Grinding Station triggers, untapping Grinding Station.
6. Repeat.

This crafty loop uses Bolas's Citadel to cast spells directly from the top of your library by paying life instead of mana, turning your deck into a free-to-play hand. You sacrifice Phyrexian Walker to Grinding Station, which kicks off a self-sustaining cycle: Mortuary catches the creature as it hits the graveyard and tucks it right back onto the top of your library, while Grinding Station's own untap ability triggers when the artifact creature re-enters. Because Phyrexian Walker costs zero life to recast off the Citadel, you can repeat this process indefinitely to mill your opponents out completely while generating infinite storm count and death triggers.